Michigan farmers who are seeing weeds that used to be controlled by herbicides but are now surviving can get their weeds tested for herbicide resistance at Michigan State University Plant & Pest Diagnostics.
The testing process involves cleaning and growing weed seeds in the greenhouse, and then treating them with up to seven different herbicides. A known susceptible population of the same weed species is also tested to verify the results. The duration of the process depends on the species, but results are usually available no later than March.
Soybean and vegetable growers in Michigan may qualify for free screening of certain weed species. The cost of screening for non-soybean or for species not listed above for soybean growers is $90 per sample.
Most weed seeds from summer annual species mature by September to October. Farmers who plan to submit a sample for herbicide resistance testing should refer to the factsheet "Tips for Collecting Weed Seeds" to ensure that they collect mature seeds and gather a sufficient quantity. A submission form is also needed with the sample, which can be found at the link in the article.
Please submit all samples no later than November 17, 2023, to ensure testing over the winter months.
Further information on herbicide-resistant weed species confirmed in Michigan can be found on the “History & Map of Herbicide-Resistant Weeds in Michigan”
Categories: Michigan, Crops